Pain is one of the most costly and pervasive public health problems threatening the Untied States. While ethnic disparities in pain and its treatment have been reported, the influence of ethnicity on responses to analgesics has received scant attention. This study will use a common acute clinical pain model to identify and characterize psychosocial, physiological and genetic factors that contribute to ethnic group differences in pain perception and analgesia. Aim 1 will determine ethnic group differences in perceptual and physiological responses to acute post-operative pain and to examine how those are related to genetic, pre-operative psychophysical and psychosocial factors. Aim 2 will determine ethnic differences in opioid analgesia and side effects and to examine genetic, pharmacokinetic (PK), pharmacodynamic (PD), and psychosocial factors that explain group differences in analgesic responses. 200 African American and white adults (age range 18-55) who undergo third molar extraction will be included in this study. We will assess preoperative experimental pain responses and psychosocial measures. We will monitor postoperative pain levels along with PK and PD responses to the opioid fentanyl. We will assess group differences in post-operative pain as well as analgesic responses immediately for several hours post surgery and up to 3 days post-procedure. My objectives are designed to establish a foundation upon which to build an independent research career in clinically-relevant experimental neuroscience pain research. The proposed training and mentored research will ultimately enhance my understanding of biopsychosocial factors that contribute to health disparities. I propose 4 main training objectives: 1) Develop expertise in psychophysical and clinical pain assessment with emphasis on ethnic differences;2) Gain an understanding of the complex genetic, PK/PD processes involved in post-operative pain and analgesic responses;3) Increase knowledge in advanced biostatistical methodology;and 4) Improve understanding of factors related to ethnic differences acute pain and analgesia. My long-term career goal is to develop a programmatic line of research designed to elucidate biopsychosocial contributions to ethnic differences in pain. Eventually, I would engage in translational research to reduce health disparities in clinical pain through the development of interventions designed to enhance the quality of life of individuals with pain, consistent with the strategic plan of NINDS.